Autoimmune diseases result from an abnormal immune response to self antigens. In autoimmune diseases in which the destruction of self tissue results in a metabolic deficiency, some treatment approaches are directed at replacing the deficient element. For example, patients suffering from insulin dependent diabetes mellitus (IDDM) are treated by administering insulin, and pernicious anemia patients are treated with vitamin B.sub.12. Even under the best of circumstances, such treatments do not even address, much less reverse, the underlying immunological cause of the deficiency.
Immunological control strategies primarily have been directed either at specific, individual antigens, or at general regulatory processes. As discussed in more detail below, approaches directed at specific antigens first require accurate identification of the offending antigen. Furthermore, many pathological autoimmune responses target more than one single antigen, complicating both the process of antigen identification and the treatment strategy. Also discussed below, immunoregulatory approaches such as treatment with immunosuppressive or anti-inflammatory drugs invariably lead to detrimental effects owing to the systemic influence of the agents on the immune system.